Flexible tubular conduits made primarily of elastomeric materials are in wide use throughout industry whereby numerous manufacturers are engaged in making and selling such conduits, resulting in a highly competitive industry.
It has been found that tubular conduits of this type are often used for vacuum cleaner hoses or conduits and a typical vacuum cleaner conduit has one or more reinforcing wires wound in a helical pattern along the length of the conduit and an elastomeric sleeve usually made of a plastic material is provided around the reinforcing wire or wires.
It is generally very difficult if not impossible to produce a high quality vacuum cleaner conduit (i.e., one with precisely controlled wall thickness and diameter) of the character mentioned without producing such a conduit on a rigid mandrel of substantial length, such as of at least several feet and preferably of the order of 50 feet and even more. However, in manufacturing such a conduit on a rigid mandrel of such a substantial length, it is ordinarily very difficult to remove the mandrel from within the flexible tubular conduit in a simple and efficient manner without damage to the conduit and its supporting mandrel.